Then our ranger, who is sitting cross-legged on the bow, flicks on his torch. The white beam cuts through the nothingness until it catches the reflection of a pair of submerged eyes. They belong to a saltwater crocodile.

He adjusts the light’s position to the left, then to the right, revealing two more pairs of eyes.

‘It is high tide, and they like to hunt now,’ he says in a hushed voice. ‘But don’t worry, they are only small. No threat to humans for a few more years.’

Borneo is the largest island in Asia. It is a highly efficient ecosystem of dense, steamy rainforest.

Sir James Brooke, a British colonialist, undertook mammoth expeditions here in the 19th century to bring order to a violent and chaotic tribal land.

In those days, the Dayak, a collective term for the indigenous people of Borneo, practised the ancient tradition of headhunting.

This involved the taking of heads between warring tribes. Nowadays, you are more likely to find yourself in a Bornean jungle spa having a head massage.

We are one hour north of Kota Kinabalu, Borneo’s capital. My wife’s grandfather worked here for five years as an accountant in the Commonwealth Development Corporation during the Seventies.

It feels as though little has changed since then.

There is one Canary Wharf-style office tower and the younger locals are ambitious for a more cosmopolitan existence.

However, they are immensely proud of their heritage and constantly direct our attention to the country’s true natural powerhouse — Mount Kinabalu.

At 13,435 ft, it is the highest mountain between the Himalayas and New Guinea.